In: PLOS ONE, 2017, vol. 12, no. 10, p. e0186840
Here we made an attempt to obtain partial structural information on the topology of multispan integral membrane proteins of yeast by isolating organellar membranes, removing peripheral membrane proteins at pH 11.5 and introducing chemical crosslinks between vicinal amino acids either using homo- or hetero-bifunctional crosslinkers. Proteins were digested with specific proteases and the...
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In: Glycobiology, 1998, vol. 8, no. 8, p. 761-770
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In: Glycobiology, 2006, vol. 16, no. 2, p. 155-164
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In: Rapid Communications in Mass Spectrometry, 2016, vol. 30, no. 20, p. 2215–2227
Rationale: Suppressor lipids were originally identified in 1993 and reported to encompass six lipid classes that enable Saccharomyces cerevisiae to live without sphingolipids. Structural characterization, using non-mass spectrometric approaches, revealed that these suppressor lipids are very long chain fatty acid (VLCFA)- containing glycerophospholipids with polar head groups that are...
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In: PLOS Genet, 2016, vol. 12, no. 7, p. e1006160
While most yeast enzymes for the biosynthesis of glycerophospholipids, sphingolipids and ergosterol are known, genes for several postulated transporters allowing the flopping of biosynthetic intermediates and newly made lipids from the cytosolic to the lumenal side of the membrane are still not identified. An E-MAP measuring the growth of 142'108 double mutants generated by systematically...
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In: PLOS ONE, 2016, vol. 11, no. 1, p. e0145831
Ceramide is synthesized in yeast by two redundant acyl-CoA dependent synthases, Lag1 and Lac1. In lag1∆ lac1∆ cells, free fatty acids and sphingoid bases are elevated, and ceramides are produced through the redundant alkaline ceramidases Ypc1 and Ydc1, working backwards. Even with all four of these genes deleted, cells are surviving and continue to contain small amounts of complex...
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In: Biochimica et Biophysica Acta (BBA) - Biomembranes, 2015, vol. 1848, no. 11, Part A, p. 2960–2966
Acyl-Coenzyme A is made in the cytosol. Certain enzymes using acyl-CoA seem to operate in the lumen of the ER but no corresponding flippases for acyl-CoA or an activated acyl have been described. In order to test the ability of purified candidate flippases to operate the transport of acyl-CoA through lipid bilayers in vitro we developed three enzyme-coupled assays using large unilamellar vesicles...
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In: Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 2015, vol. 1851, no. 5, p. 629–640
Five yeast enzymes synthesizing various glycerophospholipids belong to the CDP-alcohol phosphatidyltransferase (CAPT) superfamily. They only share the so-called CAPT motif, which forms the active site of all these enzymes. Bioinformatic tools predict the CAPT motif of phosphatidylinositol synthase Pis1 as either ER luminal or cytosolic. To investigate the membrane topology of Pis1, unique...
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In: FEMS Yeast Research, 2014, vol. 14, no. 5, p. 776–788
Humans and yeast possess alkaline ceramidases located in the early secretory pathway. Single deletions of the highly homologous yeast alkaline ceramidases YPC1 and YDC1 have very little genetic interactions or phenotypes. Here, we performed chemical-genetic screens to find deletions/conditions that would alter the growth of ypc1∆ydc1∆ double mutants. These screens...
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In: Biochemical Journal, 2013, p. -
Ypc1p and Ydc1p are alkaline ceramide hydrolases, which reside in the ER. Ypc1p can catalyze the reverse reaction, i.e. the condensation of free fatty acids with phytosphingosine or dihydrosphingosine and overexpression of YPC1 or YDC1 can provide enough ceramide synthesis as to rescue the viability of cells lacking the normal acyl-CoA-dependent ceramide synthases. To better understand the...
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